Question

Write the equations involved in the following reaction:

$A$: Reimer-Tiemann reaction

$B$: Kolbe's reaction

Answer 1

$A$:

Reimer - Tiemann reaction
When phenol is treated with chloroform in the presence of sodium hydroxide, a $-CHO$ group is introduced at the ortho position of the phenol. This reaction is known as the Reimer-Tiemann reaction. The intermediate (substituted benzal chloride) is hydrolyzed in presence of alkali to produce salicylaldehyde.

Reaction involved
The reaction involved in Reimer - Tiemann reaction is -


$B$:
Kolbe’s reaction

When phenol is treated with sodium hydroxide, sodium phenoxide is produced. This sodium phenoxide when treated with carbon dioxide (which acts as electrophile), undergoes electrophilic substitution, followed by acidification to give ortho-hydroxybenzoic acid as the main product. This reaction is known as Kolbe's reaction.

Reaction involved
The reaction involved in Kolbe’s reaction is -